298 BACON. 



Duclaux, in France, giving an exposure during the hours from 8 a. in. to 

 4 p. m.j at Mont Dore in August and September, 1888, obtained an average of 

 18.3 per cent of decomposition; this special series being lower than usual. A 

 decomposition of 50 per cent was very usual in France. However, in a series 

 from May 9 to June 11, 1888, at Helsingfors, there was, on the average, nearly 

 50 per cent decomposition, whereas in Algeria only about 9 per cent was found. 



Other figures in the literature which are of some value for com- 

 parison with the Manila results are as follows: 



De Vries 20 working in Holland, found from 5 to 25 per cent decomposition 



N 

 for 10 cubic centimeters of — oxalic acid in the sun for 8 hours, and in one 



instance 50 per cent. Jorisson and Reicher 2T studied the decomposition of oxalic- 

 acid in sunlight, especially with reference to the effect of small additions of 

 acids, alkalis and metallic salts. It is impossible to compare their results 

 directly with mine for elimatologic purposes, as they say they exposed their 

 solutions in large flasks, without giving the exact dimensions of the latter, 

 but it is evident that the reaction was much slower than in Manila. Thus, in 



N 

 one case for seven days of sunlight with 10 cubic centimeters — solution, the 



oxalic acid was decomposed to the extent of only 12 per cent. Jorisson says 

 nothing concerning the marked increase in the rate of decomposition with the 

 time of exposure, but his results show this phenomenon very clearly. Thus, for 

 two days, 15.9 per cent were decomposed, for five days, 100 per cent. 



Days. Per cent. 



1.5 16.7 



2.5 37.5 



4.5 9.1.7 



1.5 . 8.7 



3.0 39.1 



5.0 93.5 



Sulc - a working in Prag in the summer of 1898, gives the following figures 



N 

 for 10 cubic centimeters — oxalic acid. 



10 



Days. Titre. 



10.04 



4 9.92 



19 6.40 



38 0.34 



26 Verslagen en medcelingen der konenklijke Academie von Wetensohaften (188), 

 (3), 1, 114. 



27 Ztschr. f. phys. Chem. (1899), 31, 142. 

 ™lbid (1899), 28, 719. 



